Constanz schmitz



(No Model.)

' c. SOHMITZ. METHOD OF AND APPARATUS FOR MIXING GOAL DUST AND AIR FOR COMBUSTION.

No. 540,114. Patented May 28, 1895.

WITNESSES.

INVENTOH: i"?

rm/mars NIT'ED STATES PATENT OFFICE,

CONSTANZ SCHMITZ, OF BERLIN, GERMANY.

METHOD OF AND APPARATUS FOR MIXING COAL-DUST AND AIR FOR COMBUSTION.

IE P-ECIFICATIQN forming part Of Letters Patent NO. 540,114, dated May 28, 1895.

Application filed July 2,1 894. Serial No. 516,407- (No model.)

To all whom it may concern:

Beit known that I, OoNsTANZ ,SoHMITz, a subject of the King of Prussia, Emperor of Germany, residing at Berlin, in the Kingdom of Prussia, Germany, have invented a new and j useful Method of and Apparatus for Mixing Goal-Dust and Air for Combustion, of which the following is aspecification.

All the coal-dust firings hitherto used have the inconvenience, that the ground coal is introduced by means of any suitable mechanical device directly into the firing place. In consequence thereof an intimate mixture of coal and air is not obtained and a portion of the coal escapes unburned and falls down in the flues or it passes as smoke into the chimney. Moreover the quantity of the introduced coal cannot be rendered dependent upon the air quantity, so that with an increased air quantityacorrespondinglygreater quantityof coal is not introduced into the fire place; but the effect hereby produced is quite contrary to the intended purpose as the excess of cold air cools the firing place and prevents thus the ignition and good combustion of the coal; besides the feeding devices very often refuse the service, because any larger grain, the coal agglomerated by moistness, or a thread of the coal sacks hinders the feeding. By this the regularityof the working is put in question as it has been shown by practice. Finally it is impossible to force the firing with the hitherto known means. These inconveniences can be obviated by preparing an intimate mixture of coal dust and air, which always is composed in the manner necessary for obtaining the most advantageous combustion of the kind of coal to be taken into consideration. Such a mixture stored up and introduced into the furnace as required, will always afford a faultless and smokeless combustion. The right composition and the required uniformity of the mixture can be attained only without the fire place. A separation of the pure coal-dust from the impurities contained in the ground coal must precede the preparation of the mixture. To effect this separation directly the same air is used, which afterward is to be mixed with the coal-dust, and in such a manner, that the ground coal is introduced into an air current and carried along with it for some time. The impurities and larger pieces then fall down, asthe velocity of the air cur rent may be so taken, that only the finest coal dust particles can be carried by the current.

The air and the fine coal dust enter then together into a separate room, where they are stored up as a finished mixture and introduced as Wanted, .into the fire place. In this storeroom the air is held in a continuous movement. The air, corresponding to the speed, with which it moves, will hold in suspension only a quite determined percentage of coal-dust. If therefore coal-dust is introduced in excess into the store-room, the air will be saturated only Wit-l1 the percentage of coal dust corresponding to the velocity with which it moves in the store-room. By altering the velocity of the air, the percentage of the composition of the mixture of air and coal dust may therefore also'be altered corresponding to the burning value of the kind of coal employed. When from the store room a certain quantity of air is fed into the fire place, at the same time so large a quantity of coal dust will be taken along as under the conditions obtaining the air quantity will be capable to burn. A decrease or increase of air supply will cause at once a corresponding decrease or increase of the quantity of coal, as the percentage of the composition of the mixture is always the same. I This percentage of the composition is altered only by the velocity of the air in the store-room independent of the quantity of air taken therefrom.

'The accompanying drawing shows, by way of example, a device, which may advantageously be employed for carrying out the process.

From a funnel A the ground coal is led by means of a feeding roller or another suitable device B into an air current produced by a blowing engine or a windwheel O or by any other suitable means. The air current may also be produced, say by utilizing only the sucking efiect of a second blowing engine G. This air current carries the coal through a channelD into the store-room F. In this way the air currentcorresponding to the velocity, with which it moves, allows all the parts heavier than the fine coal dust, to fall down. These parts, say coarser coal pieces, mineral admixtures and the like are collected in a vessel E. In the store-room F the air, maintaining in suspension the coal dust arriving from the channel D is put in motion by means of a blowing engine or windwheel G or by another suitable device or only by the efiect of the first wind wheel E. The velocity of the airis' so, that it maintains in suspensionexactly so large a quantity of coal dust as, under the conditions obtaining, can be burned in the most advantageous manner. When a larger quantity of coal dust is introduced than the air in motion is capable to maintain in suspension, it falls down and is collected on the bottom of the store-room, whence from time to time it is discharged into a vessel H placed underneath the store-room F. From the storeroom the mixture of coal dust and air is carried off through one or more con-duit pipesJ and led by means of :a blowing engine or by the natural draft into one-or moreifilre places. f The combustion takes place here in a known way, say onsurfacesmade of fire bricks, while for starting the plant thei' plane grate or another firing already in use may be employed; It will be observed that the storage cham-= her is of increased cross sectional area rela-i tively to its inlet and outlet, so that the ai-rj in said chamber instead of traveling in at? straight line from the inlet to the outileuwilh be subjected to an eddying agitatiomto hold; the coal dust in suspension,and this effect is; further improved by producing-a circuitous} channel in the storage chamber, as shown; and placing-the blowing-engine G in the saidg channel. I-Iavingnowfully described andascertained the nature of mysaid :invention and in what manner the same is to be performed, I declare 1. that what I claim is- 1. The herein described methodaof treatingi coal dust fuel, which consists in feeding the? sameinto-acham-ber agitating thebodyof ai contained in said chamber zwithout 'dxirectl' expelling it therefrom,:and feeding to the f ur-; nace as required, "the mixture of air and su-s-TE pended coal dust, substantially as described. 2. The herein describedmetho'd'of treating; coal dust fuel, whichconsists in fieeding the i same into a chamber, producing an eddying agitation of air in said chamber to hold the coal dustin suspension, and feeding to the furnace as required, the mixture of air and suspended coal dust, substantially as described.

3. An apparatus for mixingcoal dust with air, consisting of a feed device for the coal, a

' storage chamber having an inlet connected to the feed device, and an outlet adapted for connection with a furnace, said storage chamber being of enlarged cross sectional area rel atively to the inlet and the outlet, and a blowing engine for producing a current of air in the storage chamber, substantially as. described.

4. An apparatus for mixing coal dust with air, consisting of a'feed device for the coal, a storage chamber having an outlet adapted for connection with afurnace, achannel connecting the feeddevice with the storage chamber, and provided with an outlet for coarse particles, and the blowing engine for producing a current of air in the said channel and storage chamber, substantially as described.

5. An apparatus for mixing coal dust with air consisting-of a feed device for the coal, a :storagechamlber having an inlet connected to the feed device,an outlet adapted for connection with a furnace, and a circuitous channel and agblewi-ng engine for producing acurrent of air in the storage ohamber,.substantially as described.

6. An apparatus for mixing :coal dust with tion with a furnace, and a circuitous channel,

, and a :blow-in-gengine located'in said channel to agitatetheairzin the storage chamber, sub- ;st-an tiall y as described.

In testimony whereof I have signed my name to "this specification in the presence of "two subscribing witnesses.

, CONSTANZ SOHMITZ.

Witnesses:

EDUARD PEITZ, GUSTAV HiiLsMANN. 

